Voice disorders result from the disruption of normal vocal fold vibration during phonation. The current gold standard for assessing voice disorders is visual endoscopic examination via videostroboscopy. However, technical limitations that are inherent to stroboscopic imaging (i.e., generating a composite image that is assembled across many cycles of vibration) restrict the clinical and research utility of videostroboscopy. High-speed imaging has the potential to capture the true cycle-to-cycle vibratory behavior of the vocal folds, which should theoretically overcome the limitations of videostroboscopy, and provide the potential for more accurate objective quantification of vocal fold vibratory behavior. Vocal fold high-speed imaging has a long research history, and the relatively recent commercial introduction of laryngeal high-speed videoendoscopy (HSV) has served to increase its availability for clinical and research use. However, these HSV systems have not gained widespread adoption because of remaining methodological limitations (eg., compromised image quality;lack of tools to extract the rich visual content, difficulty managing and analyzing the massive amounts of data generated by HSV, etc.), and an associated lack of information regarding the validity, practicality, and clinical relevance of HSV. The primary purpose of this project is to develop improved HSV-based methods for the visualization and automatic measurement of vocal fold vibratory characteristics that will facilitate the clinical and research use of this technology, and to begin establishing the clinical validity, practicality, and relevance of HSV in the functional evaluation of vocal fold pathology. The overriding hypothesis is that HSV can be developed into a robust tool that will provide new insights into the biomechanics of laryngeal sound production (particularly when combined with other simultaneous measures), as well as enable more accurate functional assessment of the pathophysiology of voice disorders leading to important refinements in the diagnosis of vocal fold pathology. The primary purpose requires a series of experiments to improve HSV technology, develop analysis techniques, establish a clinical protocol, collect data, and evaluate the reliability, validity, and relevance of HSV in the clinical assessment of voice disorders. This project proposes a comprehensive approach addressing all of the above tasks, through the collaboration of leading scientists and clinicians.